The Research Of Methods In Superposition Of Multi-Harmonics Sources In Electrical Traction System

With the rapid development of national economics and electricity markets, power quality issues have captured considerable attention from both utility companies and their customers in many countries, in part due to the proliferation of sensitive electronic equipment. A poor supply quality can degrade the quality of products, influence the work of many transportation and producing departments, so make a great deal of losses in economics.Especially in electrical railway, because of tractor locomotives' to and fro and particularity of electrical load, it is always hard to superpose multi-tractors' harmonics currents. Many experts and researchers have made great efforts in a long time.This paper is from the study of theory, analysis the particularity of electrical tractor loads. Based on the facts in our country, this paper raised that the method of probability should be used in electrical tractor system. And at the same time, the main problems and Availableln of this method. Based on MATLAB, the model of probabilistic method and Monte Carlo simulation in superposition multi-harmonics sources are compared. So the probabilistic method is confirmed. The pictures ofprobabilistic characteristic in both sides of impendence matching balance transformers are drawn, and probabilistic density figures are also given.The simulation model of ShaoShan 4 electrical tractor is raised, at the same time facing the restriction of probabilistic method, the paper raised that using Monte Carlo simulation absorbed harmonics currents of the model of electrical tractor and simulated the superposition of low harmonics currents. Through compared with real time data, the Monte Carlo simulation can be confirmed, and the breakthrough point of restriction of using probabilistic method is discussed.